1. Field of the Invention
The present invention relates to a compact high-frequency circuit device that operates in a high frequency range, particularly, in an extremely high frequency (EHF) range of 30 GHz or more.
2. Description of the Related Art
FIG. 18 is a plan view showing a conventional high-frequency semiconductor package.
In FIG. 18, reference numeral 200 designates a semiconductor package; 201 designates a package housing; 202 designates a semiconductor chip typified by a monolithic microwave IC (MMIC); 203 designates a cavity in which the semiconductor chip 202 is to be mounted; 204 designates a bonding wire; 205 designates a microstrip line; 206 designates a cavity wall; and 207 designates a feedthrough. The feedthrough 207 comprises a microstrip line 207a, a strip line 207b, and a microstrip line 207c, which penetrate through the cavity wall 206.
Reference numeral 208 designates an isolation resistor; reference numeral 209 designates a signal distribution circuit; and reference numeral 210 designates a signal composition circuit.
FIG. 19 is a perspective view showing the package housing 201 of the conventional high-frequency circuit device shorten in FIG. 1. After the semiconductor chips 202 have been mounted on the package housing 201, the package housing 201 is encapsulated with a cover (not shown).
Here, the expression xe2x80x9csemiconductor packagexe2x80x9d used herein generally designates a package formed by means of encapsulating a single-function MMIC chip in a package housing.
In the conventional high-frequency semiconductor package 200, for example, two semiconductor chips are arranged in a side-by-side configuration. In this configuration, a plurality of semiconductor chips 202, the signal distribution circuit 209, and the signal composition circuit 210 are disposed in a common plane. The signal distribution circuit 209 and the signal composition circuit 210 usually require lines having lengths which are about one-quarter the wavelength of the frequency employed by the high-frequency semiconductor package 200. For this reason, the in-plane area of the cavity 203 cannot be made sufficiently small, which imposes difficulty in miniaturizing the high-frequency semiconductor package 200.
Further, the in-plane area of the cavity 203 becomes prone to increase, thereby facilitating occurrence of spatial resonance attributable to cavity size.
Further, in a case where two semiconductor chips, for example, are disposed in a side-by-side configuration, the degree of isolation between the semiconductor chips 202 is generally low. For this reason, there may often arise leakage of a signal. A ground conductor layer having openings is interposed between dielectric layers, and a signal is transmitted through one of the openings. Similar configurations are described in, for example, Japanese Patent Laid-Open Nos. Hei. 11-163185, Hei. 9-237867, Hei. 8-250913, Hei. 8-250911, Hei. 10-303616, Hei. 195732, Hei. 10-270586 and Hei. 10-176113. These configurations are only for transferring by means of electromagnetic coupling via an opening.
These configurations correspond to a one input/one output circuit and are merely intended to transmit a signal between layers.
The present invention has been conceived to solve such a problem of a conventional high-frequency semiconductor package as mentioned above, and is aimed at providing a compact high-frequency circuit device comprising a distribution circuit and a composition circuit. Further, the present invention is aimed at providing a compact high-frequency circuit device that achieves a superior electric characteristic even when a plurality of semiconductor chip is packaged.
According to one aspect of the present invention, the foregoing and other objects are attained by providing a high-frequency circuit device having a multi-layer circuit as follows. The multi-layer circuit comprises: a first conductor for transmitting a signal; a first dielectric layer inserting the first conductor; a first ground conductor layer which is provided on one surface of the first dielectric layer and has a first opening; a second ground conductor layer which is provided on the other surface of the first dielectric layer and has another first opening, the openings of the first and second ground conductor layers being mutually opposed by way of the first dielectric layer; second dielectric layers, one being provided on the surface of the first ground conductor layer and the other being provided on the surface of the second ground conductor layer; and a pair of second conductors for transferring a signal, one being provided on the surface of one of the second dielectric layer and the other being provided on the surface of the other of the second dielectric layer, portions of the second conductors being mutually opposed via the first openings.
Accordingly, a signal distribution circuit and a signal composition circuit are formed into a multi-layer structure. Thus, the signal distribution circuit and the signal composition circuit can be made compact. As a result, there can be embodied a compact high-frequency circuit device.
In accordance with another aspect of the present invention, the foregoing and other objects are attained by providing a high-frequency circuit device comprising an input multilayer circuit, an output multilayer circuit and semiconductor elements as follows. The input multi-layer circuit including; a first conductor for transmitting an input signal, a first dielectric layer inserting the first conductor, a first ground conductor layer which is provided on one surface of the first dielectric layer and has an input opening, a second ground conductor layer which is provided on the other surface of the first dielectric layer and has another input opening, the input openings of the first and second ground conductor layers being mutually opposed through the first dielectric layer, second dielectric layers which are respectively provided on the surfaces of the first and second conductor layers so as to expose portions thereof, and a pair of second conductors for transmitting an input signal which are provided on the surfaces of the respective second dielectric layers, portions of the second conductors covering portions of the first conductor, and the second conductors being mutually opposed by way of the input openings. The output multi-layer circuit including; a third conductor for transmitting an output signal, the first dielectric layer inserting the third conductor, the first ground conductor layer which is provided on one surface of the first dielectric layer and has an output opening, the second ground conductor layer which is provided on the other surface of the first dielectric layer and has another output opening, the output openings of the first and second ground conductor layers being mutually opposed through the first dielectric layer, the second dielectric layers which are respectively provided on the surfaces of the first and second conductor layers, and a pair of fourth conductors for transmitting an output signal which are provided on the surfaces of the respective second dielectric layers, portions of the fourth conductors covering portions of the third conductor, and the fourth conductors being mutually opposed by way of the output openings. The semiconductor elements are provided in respective exposed portions formed in the first and second ground conductor layers, one semiconductor element being connected to the second conductor and the fourth conductor on one side, and the other semiconductor element being connected to the second conductor and the fourth conductor on the other side.
Accordingly, there can be embodied a compact high-frequency circuit device having a plurality of semiconductor elements, and distribution/composition circuits.
Other objects and advantages of the invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific embodiments are given by way of illustration only since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.